1. Field of the Invention
The present invention is in the field of inhibitors of plasminogen activator inhibitor-1 (PAI-1) activity. More particularly, the invention relates to the use of substituted thiazoles as inhibitors of PAI-1, and to novel classes of 2-substituted thiazole derivatives, their synthesis and their use as inhibitors of PAI-1.
2. Related Art
PAI-1 is a naturally occurring serine protease inhibitor, or serpin, that rapidly inhibits the activity of several proteases, including tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA), by forming equimolar, irreversible complexes that are internalized and degraded. In this capacity, PAI-1 plays a major role in preventing fibrinolysis by decreasing the level of tPA and/or uPA, and consequently, the level of plasminogen converted to plasmin. Plasmin is an enzyme critical to the lysis of fibrin clots and works by cleaving fibrin to small soluble products.
PAI-1 can contribute to a variety of coronary diseases by retarding the clearance of thrombi. Elevated levels of PAI-1 have been described to correlate with an increased risk of atherosclerosis (Lupu, F., et al., Arteriosclerosis and Thrombosis 13:1090-1100 (1993)), deep vein thrombosis (Patrassi, G. M., et al., Fibrinolysis 6:99-102 (1992)) and of thrombosis during sepsis, surgery and trauma (Kluft, C., et al., Scand. J. Clin. Lab. Invest. 45:605-610 (1985)). Elevated PAI-1 levels are also thought to contribute to the high incidence of coronary disease in individuals with Type 2 diabetes (Sobel, B. E., et al., Circulation 97(22):2213-2221 (1998)), obese individuals (Lundgren, C. H., et al., Circulation 93(1):106-110 (1996)), and the elderly (Lupu, F., et al., Arteriosclerosis and Thrombosis 13:1090-1100 (1993)).
Increased PAI-1 has been demonstrated in human atherosclerotic vessel walls and may contribute to the impaired plasma fibrinolytic capacity in patients at high risk of atherothrombotic events. The atherosclerotic process begins with an injury to the inner lining of the blood vessel, the endothelium. Smooth muscle cells migrate from their normal location in the media to the intima, where they divide and make up a bulk lesion.
Immunohistochemical analyses have revealed that most of the PAI-1 in the thickened intima of early lesions is located in and around neointimal smooth muscle cells and possibly macrophages. Both of these cell types can become lipid-laden foam cells that form fatty streaks, another hallmark feature of atherosclerosis.
In advanced lesions, larger amounts of PAI-1 are expressed by smooth muscle cells and macrophages in the necrotic core. Most of the PAI-1 of this advanced stage is in complex tPA, suggesting that PAI-1 has an important function in modulating mural tPA activity (Padro, T., et al., Arterioscler. Thromb. Vasc. Biol. 15:893-902 (1995) and Saweh, H., et al., Circ. Res. 73:671-680 (1993)). These findings have been supported with experimental work in rabbits that demonstrated an increase in PAI-1 expression in activated endothelial cells, macrophages and smooth muscle cells in response to sustained mechanical injury. The increase in PAI-1 transcription paralleled the severity of vascular lesions induced and was increased in hypercholesterolemic rabbits (Kruithof, E. K. O., et al., Blood 70:1645-1653 (1987)). These results suggest that enhanced PAI-1 expression is a feature of early atherosclerosis and that a PAI-1 inhibitor may be effective preventive therapeutics for high risk patients.
A PAI-1 inhibitor may also serve as an anticancer agent. An antibody to PAI-1 has been shown to suppress metastasis in several cancer models (Tsuchiya, H., et al., Gen. Diag., Pathol. 141:41-48 (1995)). In cultured lung cancer cells, PAI-1 is necessary for optimum invasion (Liu, G., et al., Int. J. Cancer 60:501-506 (1995)). Further, cancer invasion and tumor vascularization have been prevented in PAI-1 knockout mice implanted with malignant murine keratinocytes (Bajou, K., et al., Nature Med. 4(8):923-928 (1998)). This indicates that PAI-1 plays an integral role in tumor progression.
PAI-1 is also expressed at high levels by smooth muscle and endothelial cells, and it regulates the proteolytic activity surrounding the formation of blood vessels. A PAI-1 inhibitor may be suitable as an anti-angiogenic agent by hindering proper vessel formation around tumor. In fact, transduced endothelial cells that express decreased PAI-1 activity compared with normal endothelial cells were found to form large ectactic sac-like structures resembling haemangiomas when cultured in fibrin gels, suggesting abnormal vessel formation (Lawrence, D. A., et al., J. Biol. Chem. 269(21):15223-15229 (1994)).
U.S. Pat. No. 4,942,242 discloses compounds of the following Formula: 
wherein n is 3 or 4. These compounds are disclosed to be useful as inhibitors of blood platelet aggregation.
JP 61016274 describes, for example, the following thiazole derivatives that are stated to have platelet aggregation inhibitory activity: 
wherein R1 is CH2COOH or CHMeCOOH and R2, R3 and R4 are independently selected from the group consisting of H, CH3, OCH3 and Cl, and 
A need exists in the art for compounds that are potent and/or selective inhibitors of PAI-1.
It has now been discovered that thiazole derivatives of Formula I: 
or a solvate, hydrate or a pharmaceutically acceptable salt thereof, wherein
Y is xe2x80x94Nxe2x80x94, xe2x80x94C(R3)xe2x80x94 or xe2x80x94CH(R3)xe2x80x94, wherein
R3 is selected from the group consisting of hydrogen, cyano, C(CN)3, N(CN)2, trifluoromethyl, halogen, alkyl, cycloalkyl, aryl and heteroaryl radical, all of which can be optionally substituted;
Ar1 and Ar2, which can be the same or different, are an optionally substituted aryl or an optionally substituted heteroaryl radical;
m is 0 or 1, provided that when Y is xe2x80x94Nxe2x80x94 or xe2x80x94C(R3)xe2x80x94, then m is 1, and when Y is xe2x80x94CH(R3)xe2x80x94, then m is 0;
R1 is selected from the group consisting of hydrogen, alkyl, cycloalkyl, and aryl or heteroaryl radical, all of which can be optionally substituted; and
R2 is hydrogen, or an optionally substituted aryl or an optionally substituted heteroaryl radical; with the provisos that
when Y is N, R1 and R2 are hydrogen and Ar2 is an optionally substituted phenyl, then Ar1 is other than a phenyl group substituted with carboxyalkyl or an alkyl ester of carboxyalkyloxy;
when Y is N, R1 is hydrogen, and Ar2 and R2 are both a phenyl group, then Ar1 is other than a phenyl group substituted with carboxyalkyl; or
when Y is N, R1 and R2 are hydrogen and Ar2 is naphthyl, then Ar1 is other than a phenyl group substituted with carboxyalkyl,
inhibit plasminogen activator inhibitor-1 (PAI-1). These compounds can be used in the prophylaxis or for the treatment of thrombosis, angina pectoris, cerebral infarction, myocardial infarction, pulmonary infarction, intra-atrial thrombus in atrial fibrillation, deep venous thrombus, disseminated intravascular coagulation syndrome, diabetic complications, restenosis and stroke.
Accordingly, the present invention provides a method of inhibiting plasminogen activator inhibitor-1. The method comprises administering to a mammal in need thereof an effective amount of a compound of Formula I.
Also, the present invention provides a method for preventing or treating one or more of thrombosis, angina pectoris, cerebral infarction, myocardial infarction, pulmonary infarction, intra-atrial thrombus in atrial fibrillation, deep venous thrombus, disseminated intravascular coagulation syndrome, diabetic complications, restenosis, for example, after percutaneous transluminal coronary angioplasty, or stroke by administering to a mammal in need thereof an effective amount of a compound of Formula I.
A number of compounds useful in the present invention have not been heretofor reported. Thus, the present invention also provides novel thiazole derivatives included in Formula I. Also, the present invention provides a method for preparing the novel compounds included in Formula I.
Further, the present invention provides pharmaceutical and veterinary compositions for inhibiting plasminogen activator inhibitor-1, comprising an effective amount of one or more of the compounds of Formula I-VI in a mixture with one or more pharmaceutically acceptable carriers or diluents.
Additional embodiments and advantages of the invention will be set forth in part in the description as follows, and in part will be obvious from the description, or may be learned by practice of the invention. The embodiments and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
Applicants have discovered that plasminogen activator inhibitor-1 can be effectively inhibited by compounds of Formula I: 
or a solvate, hydrate or a pharmaceutically acceptable salt thereof, wherein
Y is xe2x80x94Nxe2x80x94, xe2x80x94C(R3)xe2x80x94 or xe2x80x94CH(R3)xe2x80x94, wherein
R3 is selected from the group consisting of hydrogen, cyano, C(CN)3, N(CN)2, trifluoromethyl, halogen, alkyl, cycloalkyl, aryl and heteroaryl radical, all of which can be optionally substituted;
Ar1 and Ar2, which can be the same or different, are an optionally substituted aryl or an optionally substituted heteroaryl;
m is 0 or 1, provided that when Y is xe2x80x94Nxe2x80x94 or xe2x80x94C(R3)xe2x80x94, then m is 1, and when Y is xe2x80x94CH(R3)xe2x80x94, then m is 0;
R1 is selected from the group consisting of hydrogen, alkyl, cycloalkyl, and aryl or heteroaryl radical, all of which can be optionally substituted; and
R2 is hydrogen, or an optionally substituted aryl or an optionally substituted heteroaryl radical;
with the provisos that
when Y is N, R1 and R2 are hydrogen and Ar2 is an optionally substituted phenyl, then Ar1 is other than a phenyl group substituted with carboxyalkyl or an alkyl ester of carboxyalkyloxy;
when Y is N, R1 is hydrogen, and Ar2 and R2 are both a phenyl group, then Ar1 is other than a phenyl group substituted with carboxyalkyl; or
when Y is N, R1 and R2 are hydrogen and Ar2 is naphthyl, then Ar1 is other than a phenyl group substituted with carboxyalkyl.
Therefore, these compounds can be used in the prophylaxis or for the treatment of thrombosis, angina pectoris, cerebral infarction, myocardial infarction, pulmonary infarction, intra-atrial thrombus in atrial fibrillation, deep venous thrombus, disseminated intravascular coagulation syndrome, diabetic complications, restenosis, for example, after percutaneous transluminal coronary angioplasty, and stroke.
Preferred compounds falling within the scope of Formula I include compounds wherein Ar1 and Ar2 are independently selected from the group consisting of phenyl, biphenyl, naphthyl, tetrahydronaphthyl, thienyl, benzothienyl, furyl, benzofuryl, thiazolyl, imidazolyl, isoxazolyl, pyrrolyl and pyrazolyl, any of which can be optionally substituted. More preferably, Ar1 is selected from the group consisting of phenyl, naphthyl, tetrahydronaphthyl, biphenyl and isoxazolyl and Ar2 is phenyl. Especially, Ar1 is selected from the group consisting of tetrahydronaphthyl, biphenyl and isoxazolyl.
The aryl and heteroaryl groups are preferably optionally substituted by one or more substituents independently selected from the group consisting of alkyl, halogen, haloalkyl, hydroxy, hydroxyalkyl, amino, aminoalkyl, alkoxy, alkoxyalkyl, nitro, cyano, thiol, alkylthiol, acylamino, acyloxy, carboxy, carboxyalkyl, xe2x80x94C(O)O-alkyl, xe2x80x94C(O)NH-alkyl, xe2x80x94NHR4, xe2x80x94NR4R5, phenoxy, and benzyloxy, wherein R4 and R5 are selected from the group consisting of alkyl, xe2x80x94C(O)O-alkyl, aroyl, xe2x80x94C(O)NH-alkyl, xe2x80x94Oxe2x80x94C(O)-alkyl and xe2x80x94C(O)NH-aryl. More preferably, the optional substituents are selected from the group consisting of C1-6 alkyl, fluoro, chloro, bromo, trifluoro(C1-6)alkyl, hydroxy, hydroxy(C1-6)alkyl, amino, amino(C1-6)alkyl, C1-6 alkoxy, nitro, cyano, carboxy, xe2x80x94C(O)(C1-6)alkyl, benzyloxy, C1-6 alkylamino, di(C1-6)alkylamino, xe2x80x94C(O)O(C1-6)alkyl, xe2x80x94Oxe2x80x94C(O)(C1-6)alkyl and xe2x80x94C(O)NH(C1-6)alkyl.
Preferably, R1 is selected from the group consisting of H, C1-6 alkyl, C3-7 cycloalkyl and phenyl substituted with trifluoro(C1-6)alkyl, nitro, hydroxy, C1-4 alkyl, halogen, amino, xe2x80x94NHR4, wherein R4 is selected from the group consisting of C1-6 alkyl, xe2x80x94C(O)(C1-6)alkyl, aroyl, xe2x80x94C(O)NH(C1-3)alkyl and xe2x80x94C(O)NH-aryl.
Preferably, R2 is selected from the group consisting of hydrogen and a phenyl radical optionally substituted by trifluoro(C1-6)alkyl, nitro, hydroxy, C1-6 alkoxy, halogen, amino, cyano, C1-6 alkyl and xe2x80x94NHR4, wherein R4 is selected from the group consisting of C1-6 alkyl, xe2x80x94C(O)(C1-6)alkyl, aroyl, xe2x80x94C(O)NHxe2x80x94(C1-3) alkyl and xe2x80x94C(O)NH-aryl.
Preferably, R1 and R2 are both hydrogen in Formula I.
One group of useful compounds of the invention are compounds of Formula II: 
or a solvate, hydrate or a pharmaceutically acceptable salt thereof, wherein
Ar21 is an optionally substituted aryl or an optionally substituted heteroaryl radical;
Ar22 is a substituted aryl or an optionally substituted heteroaryl radical;
R21 is selected from the group consisting of hydrogen, alkyl, cycloalkyl, and aryl or heteroaryl radical, all of which can be optionally substituted;
R22 is hydrogen or an optionally substituted aryl or an optionally substituted heteroaryl radical, with the provisos that
when R21 and R22 are hydrogen and Ar22 is substituted phenyl, then Ar21 is other than a phenyl group substituted with carboxyalkyl;
when R21 is hydrogen, and Ar22 and R22 are both a phenyl group, then Ar21 is other than a phenyl group substituted with carboxyalkyl; or
when R21 and R22 are hydrogen and Ar22 is naphthyl, then Ar21 is other than a phenyl group substituted with carboxyalkyl.
Preferably, the aryl radical is selected from the group consisting of phenyl, biphenyl, naphthyl and tetrahydronapthyl. The heteroaryl radical is preferably isoxazolyl.
Preferably, Ar22 is a phenyl group substituted with one or more of alkyl, halogen, haloalkyl, hydroxy, hydroxyalkyl, amino, aminoalkyl, alkoxy, alkoxyalkyl, nitro, cyano, thiol, alkylthiol, acylamino, acyloxy, carboxy, carboxyalkyl, xe2x80x94C(O)O-alkyl, xe2x80x94C(O)NH-alkyl, xe2x80x94NHR4, xe2x80x94NR4R5, phenoxy, and benzyloxy, wherein R4 is selected from the group consisting of alkyl, xe2x80x94C(O)O-alkyl, aroyl, xe2x80x94C(O)NH-alkyl and xe2x80x94C(O)NH-aryl. More preferably, Ar22 is a phenyl group substituted with one or more of C1-6 alkyl, fluoro, chloro, bromo, trifluoro(C1-6)alkyl, hydroxy, hydroxy(C1-6)alkyl, amino, amino(C1-6)alkyl, C1-6 alkoxy, nitro, cyano, carboxy, xe2x80x94C(O)Oxe2x80x94(C1-6)alkyl and benzyloxy.
One group of preferred compounds of Formula II are those wherein Ar21 is a phenyl group substituted with 3,4-difluoro, 2,4-difluoro, bromo, trifluoromethyl, 3,4-dichloro, and 2,4-dichloro.
One group of preferred compounds of Formula II are those wherein Ar22 is a phenyl group substituted with carboxy, cyano, nitro, trifluoromethyl, 3,5-dichloro, 3,4-dichloro, 2,4-dichloro, 2,4,5-trichloro, 3-chloro-4-bromo, 2,4-difluoro, 2,3,4-trifluoro, hydroxy and hydroxy(C1-6)alkyl.
Preferably, R21 and R22 are both hydrogen in Formula II.
Preferably, when Ar21 is an unsubstituted naphthyl or a naphthyl substituted with halogen, R21 and R22 are both hydrogen, and Ar22 is a substituted phenyl group, then the substituents in Ar22 are not selected from the group consisting of alkyl, haloalkyl, halogen, thiol, and nitro.
One group of novel and useful compounds of the invention are compounds of Formula III: 
or a solvate, hydrate or a pharmaceutically acceptable salt thereof, wherein
Ar31 is an optionally substituted aryl or an optionally substituted heteroaryl radical selected from the group consisting of biphenyl, naphthyl, tetrahydronaphthyl and isoxazolyl; and
R33-R37 are independently selected from the group consisting of hydrogen, alkyl, halogen, haloalkyl, hydroxy, hydroxyalkyl, amino, aminoalkyl, alkoxy, alkoxyalkyl, nitro, cyano, thiol, alkylthiol, acylamino, acyloxy, carboxy, carboxyalkyl, xe2x80x94C(O)O-alkyl, xe2x80x94C(O)NH-alkyl, xe2x80x94NHR4, xe2x80x94NR4R5, phenoxy, and phenyl(C1-4)alkyloxy, wherein R4 is selected from the group consisting of alkyl, xe2x80x94C(O)O-alkyl, aroyl, xe2x80x94C(O)NH-alkyl and xe2x80x94C(O)NH-aryl, provided that at least one of R33-R37 is other than hydrogen, with the proviso that
when Ar31 is an unsubstituted naphthyl or a naphthyl substituted with halogen, then one or more of R33-R37 is not selected from the group consisting of alkyl, haloalkyl, halogen, thiol, and nitro.
Preferably, Ar31 is optionally substituted biphenyl, tetrahydronaphthyl or isoxazolyl, more preferably optionally substituted biphenyl or tetrahydronaphthyl.
Optional substituents on Ar31 are preferably selected from the group consisting of hydrogen, C1-6 alkyl, halogen, hydroxy, nitro, cyano, halo(C1-6)alkyl, hydroxy(C1-6)alkyl, and carboxy.
When Ar31 is tetrahydronaphthyl, it is preferably 5,5,8,8-tetramethyl-substituted or 3-ethyl-5,5,8,8-tetramethyl-substituted.
Preferably, R33-R37 are independently selected from the group consisting of hydrogen, C1-6 alkyl, halogen, halo(C1-6)alkyl, hydroxy, hydroxy(C1-6)alkyl, amino, amino(C1-6)alkyl, C1-6 alkoxy, C1-6 alkoxy(C1-6)alkyl, nitro, cyano, thiol, C1-6 alkylthiol, C1-6 acylamino, C1-6 acyloxy, carboxy, carboxy(C1-6)alkyl, xe2x80x94C(O)Oxe2x80x94C1-6 alkyl, xe2x80x94C(O)NHxe2x80x94C1-6 alkyl, C1-6 alkylamino, di(C1-6)alkylamino, phenoxy, and benzyloxy. More preferably, R33-R37 are independently selected from the group consisting of hydrogen, C1-4 alkyl, halogen, halo(C1-4)alkyl, trifluoro(C1-4)alkyl, hydroxy, hydroxy(C1-4)alkyl, amino, amino(C1-4)alkyl, C1-4 alkoxy, nitro, cyano, C1-4 acylamino, C1-4 acyloxy, carboxy, carboxy(C1-4)alkyl, xe2x80x94C(O)Oxe2x80x94C1-4 alkyl, xe2x80x94C(O)NHxe2x80x94C1-4 alkyl, C1-4 alkylamino, di(C1-4)alkylamino, phenoxy, and benzyloxy. Most preferably, R33-R37 are independently selected from the group consisting of hydrogen, fluoro, chloro, bromo, trifluoromethyl, hydroxy, hydroxymethyl, hydroxyethyl, nitro, cyano, methoxy, carboxy, and benzyloxy.
Also, one group of novel and useful compounds of the invention are compounds of Formula IV: 
or a solvate, hydrate or a pharmaceutically acceptable salt thereof, wherein
at least one of R48-R412 is trifluoro(C1-6)alkyl and the substitutuents that are not trifluoro(C1-6)alkyl are independently selected from the group consisting of hydrogen, C1-6 alkyl, halogen, halo(C1-6)alkyl, hydroxy, hydroxy(C1-6)alkyl, amino, amino(C1-6)alkyl, C1-6 alkoxy, C1-6 alkoxy(C1-6)alkyl, nitro, cyano, thiol, C1-6 alkylthiol, C1-6 acylamino, C1-6 acyloxy, carboxy, carboxy(C1-6)alkyl, xe2x80x94C(O)Oxe2x80x94C1-6 alkyl, xe2x80x94C(O)NHxe2x80x94C1-6 alkyl, C1-6 alkylamino, di(C1-6)alkylamino, phenoxy, benzyloxy, xe2x80x94C(O)O(C1-3)alkyl, xe2x80x94Oxe2x80x94C(O)(C1-3)alkyl, and xe2x80x94NHC(O)(C1-3)alkyl; and
R43-R47 are independently selected from the group consisting of hydrogen, C1-6 alkyl, halogen, halo(C1-6)alkyl, hydroxy, hydroxy(C1-6)alkyl, amino, amino(C1-6)alkyl, C1-6 alkoxy, C1-6 alkoxy(C1-6)alkyl, nitro, cyano, thiol, C1-6 alkylthiol, C1-6 acylamino, C1-6 acyloxy, carboxy, carboxy(C1-6)alkyl, xe2x80x94C(O)O-C1-6 alkyl, xe2x80x94C(O)NHxe2x80x94C1-6 alkyl, C1-6 alkylamino, di(C1-6)alkylamino, phenoxy, and benzyloxy, xe2x80x94C(O)O(C1-3)alkyl, xe2x80x94Oxe2x80x94C(O)(C1-3)alkyl, and xe2x80x94NHC(O)(C1-3)alkyl, provided that at least one of R43-R47 is other than hydrogen, with the proviso that
when one of R48-R412 is trifluoro(C1-6)alkyl and the other substituents are hydrogen and one of R43-R47 is halogen or trifluoromethyl, then at least one of R43-R47 that is not halogen or trifluoromethyl is other than hydrogen.
Preferred compounds of Formula IV include compounds wherein at least one of R48-R412 is trifluoromethyl.
Another group of novel and useful compounds of the invention are compounds of Formula IV or a solvate, hydrate or a pharmaceutically acceptable salt thereof, wherein
at least one of R48-R412 is nitro and the substituents that are not nitro are independently selected from the group consisting of hydrogen, C1-6 alkyl, halogen, halo(C1-6)alkyl, hydroxy, hydroxy(C1-6)alkyl, amino, amino(C1-6)alkyl, C1-6 alkoxy, C1-6 alkoxy(C1-6)alkyl, cyano, thiol, C1-6 alkylthiol, C1-6 acylamino, C1-6 acyloxy, carboxy, carboxy(C1-6)alkyl, xe2x80x94C(O)O-C1-6 alkyl, xe2x80x94C(O)NHxe2x80x94C1-6 alkyl, C1-6 alkylamino, di(C1-6)alkylamino, phenoxy, benzyloxy, xe2x80x94C(O)O(C1-3)alkyl, xe2x80x94Oxe2x80x94C(O)(C1-3)alkyl, and xe2x80x94NHC(O)(C1-3)alkyl; and
R43-R47 are independently selected from the group consisting of hydrogen, C1-6 alkyl, halogen, halo(C1-6)alkyl, hydroxy, hydroxy(C1-6)alkyl, amino(C1-6)alkyl, C1-6 alkoxy, C1-6 alkoxy(C1-6)alkyl, cyano, C1-6 alkylthiol, C1-6 acylamino, C1-6 acyloxy, carboxy, xe2x80x94C(O)Oxe2x80x94C1-6 alkyl, xe2x80x94C(O)NHxe2x80x94C1-6 alkyl, C1-6 alkylamino, di(C1-6)alkylamino, phenoxy, benzyloxy, xe2x80x94C(O)O(C1-3)alkyl, xe2x80x94Oxe2x80x94C(O)(C1-3)alkyl, and xe2x80x94NHC(O)(C1-3)alkyl, provided that at least one of R43-R47 is other than hydrogen.
Preferred compounds of Formula IV include also those, wherein at least one of R48-R412 is nitro and the phenyl ring is further substituted by one or more C1-6 alkyl groups (i.e., the other of R48-R412 are hydrogen or C1-6 alkyl). Preferably, R49 and R411 are both nitro and R410 is a C1-4 alkyl group, preferably t-butyl. Optionally, the phenyl ring is further substituted by two C1-3 alkyl groups.
One group of novel and useful compounds of the invention are compounds of Formula IV or a solvate, hydrate or a pharmaceutically acceptable salt thereof, wherein
at least one of R43-R47 is cyano and the substitutents that are not cyano are independently selected from the group consisting of hydrogen, C1-6 alkyl, halogen, halo(C1-6)alkyl, hydroxy, hydroxy(C1-6)alkyl, amino(C1-6)alkyl, C1-6 alkoxy, C1-6 alkoxy(C1-6)alkyl, C1-6 alkylthiol, C1-6 acylamino, C1-6 acyloxy, carboxy, xe2x80x94C(O)Oxe2x80x94C1-6 alkyl, xe2x80x94C(O)NHxe2x80x94C1-6 alkyl, C1-6 alkylamino, di(C1-6)alkylamino, phenoxy, benzyloxy, xe2x80x94C(O)O(C1-3)alkyl, xe2x80x94Oxe2x80x94C(O)(C1-3)alkyl, and xe2x80x94NHC(O)(C1-3)alkyl; and
R48-R412 are independently selected from the group consisting of hydrogen, C1-6 alkyl, halogen, halo(C1-6)alkyl, hydroxy, hydroxy(C1-6)alkyl, amino, amino(C1-6)alkyl, C1-6 alkoxy, C1-6 alkoxy(C1-6)alkyl, nitro, cyano, thiol, C1-6 alkylthiol, C1-6 acylamino, C1-6 acyloxy, carboxy, carboxy(C1-6)alkyl, xe2x80x94C(O)Oxe2x80x94C1-6 alkyl, xe2x80x94C(O)NHxe2x80x94C1-6 alkyl, C1-6 alkylamino, di(C1-6)alkylamino, phenoxy, benzyloxy, xe2x80x94C(O)O(C1-3)alkyl, xe2x80x94Oxe2x80x94C(O)(C1-3)alkyl, and xe2x80x94NHC(O)(C1-3)alkyl.
Preferred compounds of Formula IV include also compounds wherein one or more of R43-R47 are hydroxy, carboxymethyl, C1-4 alkoxy, phenoxy, benzyloxy, carboxy, xe2x80x94C(O)O(C1-3)alkyl or xe2x80x94Oxe2x80x94C(O)(C1-3)alkyl.
One group of useful compounds of the invention are compounds of Formula V: 
or a solvate, hydrate or a pharmaceutically acceptable salt thereof, wherein
R53-R58 are independently selected from the group consisting of hydrogen, alkyl, halogen, haloalkyl, hydroxy, hydroxyalkyl, amino, aminoalkyl, alkoxy, alkoxyalkyl, nitro, cyano, thiol, alkylthiol, acylamino, acyloxy, carboxy, carboxyalkyl, xe2x80x94C(O)O-alkyl, xe2x80x94C(O)NH-alkyl, xe2x80x94NHR4, xe2x80x94NR4R5, phenoxy, and benzyloxy, wherein R4 is selected from the group consisting of alkyl, xe2x80x94C(O)O-alkyl, aroyl, xe2x80x94C(O)NH-alkyl and xe2x80x94C(O)NH-aryl.
Preferably, R53-R58 are independently selected from the group consisting of hydrogen, C1-6 alkyl, halogen, halo(C1-6)alkyl, hydroxy, hydroxy(C1-6)alkyl, amino, amino(C1-6)alkyl, C1-6 alkoxy, C1-6 alkoxy(C1-6)alkyl, nitro, cyano, thiol, C1-6 alkylthiol, C1-6 acylamino, C1-6 acyloxy, carboxy, carboxy(C1-6)alkyl, xe2x80x94C(O)Oxe2x80x94C1-6 alkyl, xe2x80x94C(O)NHxe2x80x94C1-6 alkyl, C1-6 alkylamino, di(C1-6)alkylamino, phenoxy, and benzyloxy. More preferably, R53-R58 are independently selected from the group consisting of hydrogen, C1-4 alkyl, halogen, halo(C1-4)alkyl, trifluoro(C1-4)alkyl, hydroxy, hydroxy(C1-4)alkyl, amino, amino(C1-4)alkyl, C1-4 alkoxy, nitro, cyano, C1-4 acylamino, C1-4 acyloxy, carboxy, carboxy(C1-4)alkyl, xe2x80x94C(O)Oxe2x80x94C1-4 alkyl, xe2x80x94C(O)NHxe2x80x94C1-4 alkyl, C1-4 alkylamino, and di(C1-4) alkylamino. Most preferably, R53-R58 are independently selected from the group consisting of hydrogen, fluoro, chloro, bromo, trifluoromethyl, hydroxy, hydroxymethyl, hydroxyethyl, nitro, cyano, methoxy, and carboxy.
Also, one group of useful compounds of the invention are compounds of Formula VI: 
or a solvate, hydrate or a pharmaceutically acceptable salt thereof, wherein
Ar1 and R3 are as defined for Formula I.
Useful compounds of the present invention include, without limitation:
1. 3-{[4-(5,5,8,8-tetramethyl-2-5,6,7,8-tetrahydronaphthyl)-1,3-thiazol-2-yl]amino}phenol;
2. 4-{[4-(3-ethyl-5,5,8,8-tetramethyl-2-5,6,7,8-tetrahydronaphthyl)-1,3-thiazol-2-yl]amino}benzoic acid;
3. 3-{4-(3-ethyl-5,5,8,8-tetramethyl-2-5,6,7,8-tetrahydronaphthyl)-1,3-thiazol-2-yl]amino}benzoic acid;
4. [4-(3-bromophenyl)(1,3-thiazol-2-yl)][3-(trifluoromethyl)phenyl]amine;
5. (3,5-dichlorophenyl)[4-(4-fluorophenyl)(1,3-thiazol-2-yl)]amine;
6. [4-(4-bromophenyl)(1,3-thiazol-2-yl)](3-chlorophenyl)amine;
7. [4-(3,4-dichlorophenyl)(1,3-thiazol-2-yl)](2,5-difluorophenyl)amine;
8. (3,5-dichlorophenyl){4-[4-(trifluoromethyl)phenyl](1,3-thiazol-2-yl}amine;
9. 2-{[4-(4-phenylphenyl)-1,3-thiazol-2-yl]amino}phenol;
10. 4-{[4-(4-bromophenyl)-1,3-thiazol-2-yl]amino}benzenecarbonitrile;
11. 4-{[4-(4-phenylphenyl)-1,3-thiazol-2-yl]amino}benzenecarbonitrile;
12. (2,4-difluorophenyl)[4-(4-chlorophenyl)-5-phenyl-1,3-thiazol-2-yl]amine;
13. 4-{[4-(4-phenylphenyl)-1,3-thiazol-2-yl]amino}-1,2,3-trifluorobenzene;
14. [4-(3,4-difluorophenyl)(1,3-thiazol-2-yl)](3,4-dichlorophenyl)amine;
15. [4-(4-trifluoromethylphenyl)(1,3-thiazol-2-yl)](4-nitrophenyl)amine;
16. [4-(3,4-difluorophenyl)(1,3-thiazol-2-yl) (3,5-dichlorophenyl)amine;
17. [4-(3,4-difluorophenyl)(1,3-thiazol-2-yl)](3-chloro-4-bromophenyl)amine;
18. [4-(3,4-difluorophenyl)(1,3-thiazol-2-yl)](3-trifluoromethylphenyl)amine;
19. [4-(2,4-difluorophenyl)(1,3-thiazol-2-yl)](3,4-dichlorophenyl)amine;
20. 4-{4-(3-ethyl-5,5,8,8-tetramethyl-2-5,6,7,8-tetrahydronaphthyl)-1,3-thiazol-2-yl]amino}-1-hydroxyethylbenzene;
21. 2-{[4-(5,5,8,8-tetramethyl-2-5,6,7,8-tetrahydronaphthyl)-1,3-thiazol-2-yl]amino}phenol;
22. [4-(4-trifluoromethylphenyl)(1,3-thiazol-2-yl)](3,4-dichlorophenyl)amine;
23. 4-{[4-(2,4-dichlorophenyl)-1,3-thiazol-2-yl]amino}benzenecarbonitrile;
24. (4-aminophenyl)[4-(4-chlorophenyl)-5-(4-methylphenyl)-1,3-thiazol-2-yl]amine;
25. [4-(2,4-difluorophenyl)(1,3-thiazol-2-yl)](3,5-dichlorophenyl)amine;
26. [4-(4-trifluoromethylphenyl)(1,3-thiazol-2-yl)](3-hydroxyphenyl)amine;
27. [4-(4-tert-butyl-2,6-dimethyl-3,5-dinitrophenyl)(1,3-thiazol-2-yl)](3,4,5-trimethoxypheny)amine;
28. 3-[4-(4-tert-butyl-2,6-dimethyl-3,5-dinitrophenyl)(1,3-thiazol-2-yl)amino]benzoic acid;
29. 3-[4-(4-tert-butyl-2,6-dimethyl-3,5-dinitrophenyl)(1,3-thiazol-2-yl)amino]phenol;
30. [4-(4-nitrophenyl)(1,3-thiazol-2-yl)](4-benzyloxyphenyl)amine;
31. [4-(4-nitrophenyl)(1,3-thiazol-2-yl)](2,4-dimethoxyphenyl)amine;
32. [4-(4-fluorophenyl)(1,3-thiazol-2-yl)](3,4-dichlorophenyl)amine;
33. [4-(4-chlorophenyl)(1,3-thiazol-2-yl)](3-hydroxyphenyl)amine;
34. [4-(3-chloro-4-methylphenyl)-5-methyl-1,3-thiazol-2-yl](3-hydroxyphenyl)amine;
35. (4-nitrophenyl)[4-(isoxazol-3-yl-5-carboxylic acid ethyl ester)-1,3-thiazol-2-yl]amine;
36. (2,4,5-trichlorophenyl)[4-(isoxazol-3-yl-5-carboxylic acid ethyl ester)-1,3-thiazol-2-yl]amine; and
37. 2-cyanomethyl-4-(5,5,8,8-tetramethyl-2-5,6,7,8-tetrahydronaphthyl)-1,3-thiazole.
It is also to be understood that the present invention is considered to include stereoisomers as well as optical isomers, e.g. mixtures of enantiomers as well as individual enantiomers and diastereomers, which arise as a consequence of structural asymmetry in selected compounds of the present series. The methods for separating the individual enantiomers are known to those skilled in the art.
Also, included within the scope of the present invention are the non-toxic pharmaceutically acceptable salts of the compounds of the present invention. Examples of pharmaceutically acceptable salts include inorganic and organic acid addition salts such as hydrochloride, hydrobromide, phosphate, sulphate, citrate, lactate, tartrate, maleate, fumarate, mandelate, acetic acid, dichloroacetic acid and oxalate. Acid addition salts are formed by mixing a solution of a particular aminothiazole of the present invention with a solution of a pharmaceutically acceptable non-toxic acid, such as hydrochloric acid, hydrobromic acid, fumaric acid, maleic acid, succinic acid, acetic acid, citric acid, tartaric acid, carbonic acid, phosphoric acid, oxalic acid, dichloroacetic acid, and the like. Basic salts are formed by mixing a solution of the thiazole compound of the present invention with a solution of a pharmaceutically acceptable non-toxic base, such as sodium hydroxide, potassium hydroxide, choline hydroxide, sodium carbonate, and the like.
The compounds of Formula I may also be solvated, especially hydrated. Hydration may occur during manufacturing of the compounds or compositions comprising the compounds, or the hydration may occur over time due to the hygroscopic nature of the compounds.
The term xe2x80x9carylxe2x80x9d as employed herein by itself or as part of another group refers to monocyclic or bicyclic aromatic groups containing from 6 to 12 carbons in the ring portion, such as phenyl, biphenyl, naphthyl or tetrahydronaphthyl. Preferably, the aryl group contains 6-10 carbons in the ring portion.
The term xe2x80x9cheteroarylxe2x80x9d as employed herein refers to groups having 5 to 14 ring atoms; 6, 10 or 14 xcfx80 electrons shared in a cyclic array; and containing carbon atoms and 1, 2 or 3 oxygen, nitrogen or sulfur heteroatoms (where examples of heteroaryl groups are: thienyl, benzo[b]thienyl, naphtho[2,3-b]thienyl, thianthrenyl, furyl, benzofuryl, pyranyl, isobenzofuranyl, benzoxazolyl, chromenyl, xanthenyl, phenoxathiinyl, 2H-pyrrolyl, pyrrolyl, imidazolyl, pyrazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, isoindolyl, 3H-indolyl, indolyl, indazolyl, purinyl, 4H-quinolizinyl, isoquinolyl, quinolyl, phthalazinyl, naphthyridinyl, quinazolinyl, cinnolinyl, pteridinyl, 4aH-carbazolyl, carbazolyl, xcex2-carbolinyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, phenazinyl, thiazolyl, isothiazolyl, phenothiazinyl, isoxazolyl, furazanyl and phenoxazinyl groups).
The term xe2x80x9calkylxe2x80x9d as employed herein by itself or as part of another group refers to both straight and branched chain radicals of up to 12 carbons, such as methyl, ethyl, propyl, isopropyl, butyl, t-butyl, isobutyl, pentyl, hexyl, isohexyl, heptyl, 4,4-dimethylpentyl, octyl, 2,2,4-trimethylpentyl, nonyl, decyl, undecyl, dodecyl. Preferably, the alkyl chain is 1 to 6 carbon atoms in length, more preferably 1 to 4 carbon atoms in length.
The term xe2x80x9ccycloalkylxe2x80x9d as employed herein by itself or as part of another group refers to cycloalkyl groups containing 3 to 9 carbon atoms, preferably 3 to 7 carbon atoms. Typical examples are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl and cyclononyl.
The term xe2x80x9caroylxe2x80x9d as employed herein refers to the radical Rxe2x80x94COxe2x80x94, wherein R is any of the above aryl and heteroaryl groups.
Useful halogen groups include fluorine, chlorine, bromine and iodine.
Useful haloalkyl groups include C1-12 alkyl groups substituted by one or more fluorine, chlorine, bromine or iodine atoms, e.g., fluoromethyl, difluoromethyl, trifluoromethyl, pentafluoroethyl, 1,1-difluoroethyl and trichloromethyl groups.
Useful hydroxyalkyl groups include C1-12 alkyl groups substituted by hydroxy, e.g., hydroxymethyl, hydroxyethyl, hydroxypropyl and hydroxybutyl groups.
Useful alkoxy groups include oxygen substituted by one of the C1-12 alkyl groups mentioned above.
Useful acylamino groups are any acyl group, particularly C2-6 alkanoyl or C6-10 aryl(C2-6)alkanoyl attached to an amino nitrogen, e.g., acetamido, propionamido, butanoylamido, pentanoylamido, hexanoylamido, and benzoylamido.
Useful acyloxy groups are any C1-6 acyl (alkanoyl) attached to an oxy (xe2x80x94Oxe2x80x94) group, e.g., acetoxy, propionyloxy, bytanoyloxy, pentanoyloxy, hexanoyloxy and the like.
Useful alkylamino and dialkylamino groups are xe2x80x94NHR6 and xe2x80x94NR6R7, wherein R6 and R7C1-6 alkyl groups.
Optional substituents on Ar1, Ar21, Ar31, Ar2, Ar22, R1 and R3 include any one of halogen, haloalkyl, cycloalkyl, alkyl, cycloalkylalkyl, hydroxyalkyl, carboxyalkyl, alkoxyalkyl, nitro, amino, cyano, acylamino, hydroxy, thiol, acyloxy, alkoxy, carboxy, xe2x80x94C(O)O-alkyl, xe2x80x94Oxe2x80x94C(O)-alkyl, xe2x80x94C(O)NH-alkyl, aryloxy, arylalkyloxy, xe2x80x94NHR4, xe2x80x94NR4R5 wherein R4 and R5 are selected from the group consisting of C1-6 alkyl, xe2x80x94C(O)(C1-6)alkyl, aroyl, xe2x80x94C(O)NH(C1-3)alkyl and xe2x80x94C(O)NH-aryl. More preferably the optional substituents include halogen, halo(C1-6)alkyl, cycloalkyl, C1-6 alkyl, cycloalkyl(C1-6)alkyl, hydroxy(C1-6)alkyl, carboxy(C1-6)alkyl, C1-6 alkoxy(C1-6)alkyl, nitro, amino, cyano, C1-6 acylamino, hydroxy, thiol, C1-6 acyloxy, C1-6 alkoxy, carboxy, di(C1-6)alkylamino, xe2x80x94C(O)O(C1-3)alkyl, xe2x80x94Oxe2x80x94C(O)(C1-3)alkyl, xe2x80x94C(O)NH(C1-3)alkyl, aryloxy, aryl(C1-6)oxy, xe2x80x94NHR4, wherein R4 is selected from the group consisting of C1-6 alkyl, xe2x80x94C(O)(C1-6)alkyl, aroyl, xe2x80x94C(O)NH(C1-3)alkyl and xe2x80x94C(O)NH-aryl.
The compounds of the invention may be prepared using methods known for the skilled person in the art. For example, compounds of Formula I, wherein Y is xe2x80x94Nxe2x80x94 or xe2x80x94C(R3)xe2x80x94 can be prepared by allowing a bromoketone of the Formula VII: 
wherein Ar1 and R1 are as defined above, to react with a mono- or -di-substituted thiourea of Formula VIII: 
wherein Ar2, R2 and R3 are as defined above, in an appropriate solvent, such as acetone or DMF, for a sufficient time period.
Compounds of Formula I, wherein Y is xe2x80x94CH(R3)xe2x80x94 can be prepared by allowing a bromoketone of the Formula VII to react with a thiourea of Formula IX: 
wherein R2 and R3 are as defined above, in an appropriate solvent for a sufficient time period.
The starting materials, e.g., the compounds of Formula VII, VIII and IX are either known or may be produced in known manner or analogous to the methods described herein.
PAI-1 Assay
The inhibitory activity of PAI-1 against uPA was measured by a direct chromogenic assay using the substrate N-CBZ-VAL-GLY-ARG p-nitroanilide. The tested compound was added to PAI-1 which had been diluted in activity assay buffer (0.05M Hepes, pH 7.5, 0.15M NaCl, containing 0.05% N-octyl-D-glucopyranoside and 250 xcexcg/ml bovine serum albumin). After a 10 minute incubation at 37xc2x0 C., uPA was added (0.04 units/assay), followed immediately by the addition of substrate. After reequilibration at 37xc2x0 C., residual uPA activity was quantified by measuring the change in absorbance at 405 nm over 12 minutes. The concentration of active PAI-1 in the assays was the amount required to inhibit 80-85% of uPA as compared to samples containing uPA alone.
Compositions within the scope of the invention include all compositions wherein the compounds of the present invention are contained in an amount that is effective to achieve its intended purpose. While individual needs vary, determination of optimal ranges of effective amounts of each component is within the skill of the art. Typically, the compounds may be administered to mammals, e.g., humans, orally at a dose of 1 to 1000 mg/kg, or an equivalent amount of the pharmaceutically acceptable salt thereof, per day of the body weight of the mammal being treated for thrombosis, angina pectoris, cerebral infarction, myocardial infarction, pulmonary infarction, intra-atrial thrombus in atrial fibrillation, deep venous thrombus, disseminated intravascular coagulation syndrome, diabetic complications, restenosis after percutaneous transluminal coronary angioplasty and stroke. For intramuscular injection, the dose is generally about one-half of the oral dose.
The unit oral dose may comprise from about 1 to about 1000 mg, preferably about 1 to about 100 mg of the compound. The unit dose may be administered one or more times daily as one or more tablets each containing from about 0.1 to about 50, conveniently about 0.25 to about 100 mg of the compound or its solvates.
In addition to administering the compound as a raw chemical, the compounds of the invention may be administered as part of a pharmaceutical preparation containing suitable pharmaceutically acceptable carriers comprising excipients and auxiliaries which facilitate processing of the compounds into preparations which can be used pharmaceutically. Preferably, the preparations, particularly those preparations which can be administered orally and which can be used for the preferred type of administration, such as tablets, dragees, and capsules, and also preparations which can be administered rectally, such as suppositories, as well as suitable solutions for administration by injection or orally, containing from about 0.01 to 99 percent, preferably from about 0.25 to about 75 percent of active compound(s), together with the excipient.
The pharmaceutical compositions of the invention may be administered to any animal that may experience the beneficial effects of the compounds of the invention. Foremost among such animals are mammals, e.g. humans, although the invention is not intended to be so limited.
The pharmaceutical compositions of the invention may be administered by any means that achieve their intended purpose. For example, administration may be parenteral, subcutaneous, intravenous, intramuscular, intraperitoneal, transdermal, or buccal routes. Alternatively, or concurrently, administration may be by the oral route. The dosage administered will be dependent upon the age, health, and weight of the recipient, kind of concurrent treatment, if any, frequency of treatment, and the nature of the desired effect.
The pharmaceutical preparations of the present invention are manufactured in a manner which is itself known, for example, by means of conventional mixing, granulating, dragee-making, dissolving, or lyophilizing processes. Thus, pharmaceutical preparations for oral use can be obtained by combining the active compounds with solid excipients, optionally grinding the resulting mixture and processing the mixture of granules, after adding suitable auxiliaries, if desired or necessary, to obtain tablets or dragee cores.
Suitable excipients are, in particular, fillers, such as saccharides, for example, lactose or sucrose, mannitol or sorbitol, cellulose preparations and/or calcium phosphates, for example tricalcium phosphate or calcium hydrogen phosphate, as well as binders such as starch paste, using, for example, maize starch, wheat starch, rice starch, potato starch, gelatin, tragacanth, methyl cellulose, hydroxypropylmethylcellulose, sodium carboxymethylcellulose, and/or polyvinyl pyrrolidone. If desired, disintegrating agents may be added such as the above-mentioned starches and also carboxymethyl-starch, cross-linked polyvinyl pyrrolidone, agar, or alginic acid or a salt thereof, such as sodium alginate. Auxiliaries are, above all, flow-regulating agents and lubricants, for example, silica, talc, stearic acid or salts thereof such as magnesium stearate or calcium stearate, and/or polyethylene glycol. Dragee cores are provided with suitable coatings which, if desired, are resistant to gastric juices. For this purpose, concentrated saccharine solutions may be used, which may optionally contain gum arabic, talc, polyvinyl pyrrolidone, polyethylene glycol and/or titanium dioxide, lacquer solutions and suitable organic solvents or solvent mixtures. In order to produce coatings resistant to gastric juices, solutions of suitable cellulose preparations, such as acetylcellulose phthalate or hydroxypropylmethylcellulose phthalate, are used. Dye stuffs or pigments may be added to the tablets or dragee coatings, for example, for identification or in order to characterize combinations of active compound doses.
Other pharmaceutical preparations which can be used orally include push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a plasticizer such as glycerol or sorbitol. The push-fit capsules can contain the active compounds in the form of granules which may be mixed with fillers such as lactose, binders such as starches, and/or lubricants such as talc or magnesium stearate and, optionally, stabilizers. In soft capsules, the active compounds are preferably dissolved or suspended in suitable liquids, such as fatty oils, or liquid paraffin. In addition, stabilizers may be added.
Possible pharmaceutical preparations, which can be used rectally, include, for example, suppositories, which consist of a combination of one or more of the active compounds with a suppository base. Suitable suppository bases are, for example, natural or synthetic triglycerides, or paraffin hydrocarbons. In addition, it is also possible to use gelatin rectal capsules which consist of a combination of the active compounds with a base. Possible base materials include, for example, liquid triglycerides, polyethylene glycols, or paraffin hydrocarbons.
Suitable formulations for parenteral administration include aqueous solutions of the active compounds in water-soluble form, for example, water soluble salts and alkaline solutions. In addition, suspensions of the active compounds as appropriate oily injection suspensions may be administered. Suitable lipophilic solvents or vehicles include fatty oils, for example, sesame oil, or synthetic fatty acid esters, for example, ethyl oleate or triglycerides or polyethylene glycol-400 (the compounds are soluble in PEG-400). Aqueous injection suspensions may contain substances which increase the viscosity of the suspension, and include, for example, sodium carboxymethyl cellulose, sorbitol, and/or dextran. Optionally, the suspension may also contain stabilizers.
The following examples are illustrative, but not limiting, of the method and compositions of the present invention. Other suitable modifications and adaptations of the variety of conditions and parameters normally encountered in clinical therapy and which are obvious to those skilled in the art within the spirit and scope of the invention.